Simplify Linux sig{timed}wait{info} implementations
This patch simplifies sig{timed}wait{info} by:
- Assuming __NR_rt_sigtimedwait existence on all architectures due minimum
kernel version requirement (it pre-dates Linux git inclusion for Linux
2.6.12).
- Call __sigtimedwait on both sigwait and sigwaitinfo.
- Now that sigwait is based on an internal sigtimedwait call and it is
present of both libc.so and libpthread.so we need to add an external
private definition of __sigtimedwait for libpthread.so call.
Checked on x86_64-linux-gnu.
* sysdeps/unix/sysv/linux/Versions (libc) [GLIBC_PRIVATE]: Add
__sigtimedwait.
* sysdeps/unix/sysv/linux/sigtimedwait.c: Simplify includes and
assume __NR_rt_sigtimedwait.
* sysdeps/unix/sysv/linux/sigwait.c (__sigwait): Call __sigtimedwait
and add LIBC_CANCEL_HANDLED for cancellation marking.
* sysdeps/unix/sysv/linux/sigwaitinfo.c (__sigwaitinfo): Likewise.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Zack Weinberg <zackw@panix.com>